Repair & Maintenance Log
08/11/24: Acquired game.
08/24/24: Installed one of my standard-keyed (751) locks on the coin door.
08/26/24: Printed new instruction and price cards to replace the custom cards that were in the game.
Fresh instruction and price cards.
08/28/24: New backbox bolts and washers (because I left the old ones at the seller's house). The existing legs and hardware were kind of grubby. I cleaned up the legs with some Scotch-Brite and Mean Green and reinstalled with new bolts and levelers.
08/28/24: Added remote battery backup. Instead of permanently soldering some sort of remote battery setup to the CPU board I made battery place-holders from ½" dowel. To me this is the most universal solution because no board modifications or specialized connectors are needed. The place-holders will work with any unmodified board. The battery wires are mounted to an end of each dowel with a screw and crimp terminal. The screw head becomes the "battery terminal". Don't forget to account for the height of the screw head when figuring the length of the dowel. I wired the battery pack with 8' leads. Instead of placing the battery pack in the head, I dropped it down into the body and placed it inside the coin door. Opening the coin door is easier than opening the head. The idea is that I'll be better motivated to replace the batteries more often.
My procedure was less important with this game because some previous person had already lopped off the original battery holder and plopped on something else with double-sided tape. If I ever have to pull the board, I'll replace it with a proper battery holder. Normally the lower-left terminal of the stock battery holder would be +4.5 volts and the upper right terminal would be ground. Grand Lizard is at least one exception. Grand Lizard and the previous system 9 CPU boards (along with their battery holders) are oriented 180 degrees from every other system 11 CPU.
Battery place-holders.
Battery pack inside the coin door.
Novenber, 2024-???, 2025: Shopped game.
What I have learned over the years is that I can never have too many teardown pictures. I take pictures of the area I'm about to disassemble. Then I record the type and location of hardware as it's removed. I record how any flat washers are layered. I measure each post before removing it. I take pictures of any connectors and record how wires are routed. Even if I'm convinced that something is assembled incorrectly, I still meticulously record how I found it. I took over 200 pictures just during the topside teardown.
An example of a before picture.
One of many after pictures showing the type and location of removed hardware.
Measuring a post before removal.
I should have also measured all the old rubber rings as I removed them (ominous foreshadowing).
The picture below shows the extent to which I stripped the top of the playfield. That was good enough to clean everything up with naptha and Novus 2. Here's where it got weird. The game appears to have non-factory Mylar. It was in great shape. The underling playfield finish and inserts were in great shape. But several areas outside the Mylar were somehow worn the the wood and painted white. I have no idea how such surgical destruction could have occurred to non-wear areas. Fortunately, the playfield doesn't look terrible when assembled.
Topside disassembled.
WTF?
The picture below shows the extent to which I stripped the bottom of the playfield. That was good enough to get to work on cleaning the inserts and bulbs. I could unscrew some of the lamp boards for cleaning without removing them altogether. Any discolored or otherwise suspect bulbs were replaced with new #47 or #555 bulbs.
Bottom disassembled .
I don't like disassembling/assembling mechanisms in place. And I don't like desoldering/soldering coils in place. So I now just clip the coil wires and add connectors. First I clip the wires. Then I remove the mechanism. Then I add a playfield-side connector. The mechanism-side of the connector is added at the bench as I'm servicing the rest of the mechanism.
I used the knocker assembly as my guide to establish a coil connector standard. I use three-position connectors with .093" pins. A female housing with male pins goes on the coil side of each connection. The power wires go toward the pointy side of the connectors and the control wires go toward the flat side of the connectors. The center position is left empty
Male coil connectors added under the playfield.
Below are some of the cleaned mechanisms with coil connectors and new sleeves. All the plungers were gunky. I'm thinking they had been previously lubricated.
Clean mechanisms with connectors.
The jet bumper parts were in good shape except for one broken body. Aside from cleaning, the only new parts I added were connectors, bodies, coil sleeves and LEDs.
Jet bumpers are one place I'll make a concession to LEDs. It isn't that I like LEDs, it's that I hate bumper sockets. So I take advantage of the LED's (theoretical) long life expectancy and hardwire them into the game. These LEDs don't necessarily like being soldered on. I'm quick with the soldering iron. Then I retest the LED and make sure the LED hasn't come loose in its bayonet housing.
Frosted red LEDs for the jet bumpers.
LED installed in a new jet bumper body.
Next was cleaning the cruddy, gunky drop target assemblies. Attention n00bs: don't lubricate coil sleeves! The two left-side assemblies were in good shape. All I did was disassemble and clean everything, reflow the header pins, replace the coil sleeves and add coil connectors. The right-side assembly was a bit more work with mangled header pins and lots of missing washers and e-clips. Anything under the playfield within striking distance of the prop stick was beat. Thus, the right-side assembly also received new header pins and some replacement hardware.
Mangled right-side drop target assembly.
I always prefer to keep original decals. Reproduction decals never have the right sheen. Fortunately, all the drop target decals were in good shape. They cleaned up with soap and water and some Novus 2. It seems to me that the decals should have been applied higher up on the targets. Oh well.
One out of the nine targets was cracked (from the right-side assembly, of course). So I did have to move one decal. I carefully removed the decal with a heat gun. I cleaned off the old adhesive with Goo Gone. And I applied the decal to a new target with 3M 467MP transfer tape.
Replacement targets often have defects such as flash, warps and shape imperfections. I picked the best one I had on hand. And I assembled and tested it out before risking my decal.
Clean decal ready to go on a new target.
All three of my drop target assemblies had the same arrangement of targets with the decal part numbers in numerical order. So that's how I put them back together.
Drop target decals in numerical order.
Done!
My experience with these system 11 drop target assemblies is that the opto board power connector is a point of failure. They're held with only three pins. 37 years later, they're loose. So I replaced the power connectors for all three opto boards. Also, note that the new header pins were trimmed so as to not catch on the fingers of the reset plate.
New power connector on the right-side assembly.
My left flipper coil was missing a diode. I was about to tack in a new diode when I noticed that the same diode was already broke on the right coil. Then I suspected a production issue and just replaced both coils. The replacement coils had a "tighter" diode arrangement.
Existing coil (left) compared to a replacement coil.
When rebuilding flipper mechs I like to install the new flipper bushing first. But then the assembly become awkward to handle. How about a Flipper Mech Rebuild Rack? The FMRR - otherwise known as a scrap of plywood with left and right flipper bushing clearance holes. The FMRR keeps the flipper base flat and stable and gives me something more substantial to hold while installing the remaining components.
The FMRR.
Flipper base screwed down with bushing installed.
I had a flipper rebuild kit on hand so I pretty much replaced everything. The new capacitors were frustrating because the leads were shorter than the originals. Newer kits integrate the cap head screw and crank washer. I've had issues with these pulling apart, so I reuse the old cap head screw and discrete crank washer (red arrows).
I reuse the old cap head screws and crank washers.
While I had the mech disassembled, I drilled the EOS switch bracket for an extension spring. I'm not a good enough player to tell the difference between the older compression springs and the newer extension springs, but whatever. I also turned the coils so the diodes and wiring were away from coil stop impacts.
I took an old flipper (black in this case) and cut away most of the bat. I used what remained to align the pawl and bushing. Then I could get a head start on adjusting the EOS switch before putting the mech back in the game.
FMRR with pawl/bushing alignment.
I also got a new set of flipper bats because the existing bats were the up-side-down "W" bats. That said, I didn't reinstall the slingshot and flipper mechs until the end. There was still a lot of up and down with the playfield. No sense in adding back that extra weight until I had to.
New bat (left) vs. existing bat.
The underside of the playfield had an excessive number of blown-out mounting holes. The mechanisms were mounted with self-tapping screws that seemed to have overly aggressive cutting edges. This may have been good for initial assembly, but now the holes were worn out. My usual glue and toothpick plugging solution was hit and miss because the cutting edge could immediately wreck the toothpick. Compare this to a screw from one of my older system 11 games that had no cutting edge. For future servicing I got myself a stash of non-self-tapping screws. Oddly enough, I found exactly what I was looking for at Home Depot called Teks, part #21301.
Older screw vs. newer screw.
Teks, part #21301.
The eject hole shield and corresponding microswitch bracket had spacers. I had not seen this before, but confirmed that other Jokerz! are similarly configured. However, I have not found any reference to these spacers in the manual or parts catalogs.
Eject hole shield and spacer.
Shield and microswitch spacers.
The only under-playfield mechanism I didn't mess with was the motorized ramp. It was reasonably clean and worked well. So I left it be.
Some of the BET lane guides were broke and all the star posts were in various stages of not great. So I replaced all that with new parts.
All new lane guides and star posts.
On a whim I bought a new spinner from Planetary Pinball. But it was so well balanced it would just randomly stop wherever. So I ended up going back to the existing spinner, which stops upright as it should. Trying to replace parts that don't need to be replaced can be more trouble than it's worth.
New non-working spinner (top) vs. the existing spinner.
The "Spots Card" decal for the upper left kicker was curled and misaligned. I carefully removed the decal with a heat gun. I cleaned off the old adhesive with Goo Gone. And I reapplied the decal with 3M 467MP transfer tape. Before reapplying the decal, I scanned it at 300 dpi over a one inch grid.
Before.
After.
I keep a stash of machine screws and wingnuts on hand for installing metal posts without resorting to pliers. The wingnut jams against the post and gives me something to hold while tightening the under-playfield nut.
Wingnuts for installing metal posts.
I went with a conventional white ring kit including red (per spec') flipper rubber. Unfortunately, the Jokerz! manual does not include ring mapping information. And I failed to measure the old rings as I removed them. But I found some helpful hints on the Internet to get me started and made my own main playfield ring map as I went. I'm not saying it's officially correct, but it worked for me. I didn't bother mapping the smaller bumpers and sleeving because I could figure all that from my teardown pictures. I omitted mapping for the upper mini-playfield. That'll be dealt with later.
Main playfield ring map.
Based on my game and pictures of other Jokerz!, there should be a tapered bumper (23-6579) to the right of the left ramp. But that's not included in the Rubber Parts list. I didn't have a new one on hand, so I just cleaned up the existing one.
Tapered bumper 23-6579.
The plastics on this game were decent. But Planetary Pinball had reproductions. And since the game was already apart, I bought a new set. There was a lot of riveting, which I thought would be a good warm up for replacing the upper mini-playfield. And there were some anomalies aside from the usual trimming and fitting. Maybe it was me, but I didn't think these plastics were as flexible and forgiving as what I previously experienced with plastics from CPR.
The upper-right corner plastic had a broken tip. I taped it back together with an underling piece of Mylar. Beyond that, the mounting screw securely clamped both pieces in place.
Broken upper-right corner plastic.
Broken upper-right corner plastic.
The lower-left drop target plastic had a siderail mounting hole that didn't correspond with the original plastic.
Misaligned mounting hole.
There was one leftover clear plastic, which appeared to be for the upper-right corner plastic. On my game the part was metal, which was what I reused.
Leftover plastic.
Timeout: I constantly re-tested the machine as I reassembled the playfield. While reassembling the playfield components I realized that the previously working playfield flash lamps no longer worked. Turns out I had no 25 volt power to the playfield C-side (or "orange") circuit. This traced back to a dead header pin 4 at J8 on the interconnect board. Shit.
Interconnect board removed - connector hell.
After pulling the interconnect board, the problem was obvious. The trace between J7 and J8 was blown up. This I repaired with the yellow jumper shown below. There was a physical crack in the board next to J6 which appears to have severed the trace between J6 pin 9 and fuse F4. This accounts for the green jumper added by some previous person. The board appeared to be otherwise unmolested.
Repair to J8 pin 4.
In Retrospect: I confirmed that the correct 5A slow-blow fuse was at F2C on the aux power driver board. However, when I removed the upper mini-playfield I thoughtlessly left the Z-connectors with the main playfield side of the wire harnesses. This left the orange circuit with an exposed pin. I suppose this pin could have somehow grounded as I was testing.
The three upper mini-playfield Z-connectors. Note the orange circuit in the left connector.
Takeaway: Don't be a dumbass.
The existing upper mini-playfield was yellowed and cracked. And some of the mounting holes were blown out. So I bought a new one. There appears to be some controversy regarding the new mini-playfield, which was clear, not tinted yellow. Did the old mini-playfield age to yellow or was it yellow to begin with? My own observations were inconclusive. The mini-playfield was lit with yellow light. So its actual color is difficult to dicern from old pictures.
This was a complicated assembly involving switch circuits, lamp circuits, screws, adhesives and rivets. For example, the red mini-post screws (of which some were loose) were covered over by the decal, which was covered by the switch brackets, which were riveted to the mini-playfield. Servicing was clearly not a priority. Because of all the layering, I didn't want to go back to the semi-permanent nature of riveting the switch brackets. Instead I went with truss-head 4-40 x 5⁄16" screws and nyloc nuts.
I picked truss-head screws thinking the larger, low-profile heads would better spread stress. I mocked up some parts and set the mini-playfield in the game. The ball could contact the screw head, but not before committing to a lane. That is, the screw head didn't influence the ball's lane choice.
Testing the truss-head screws.
Here's where I noticed a substantial divot over the upper lamp board's center mounting standoff. It wasn't easy to shake the ball off the divot. Others had reported a similar problem.
Mini-playfield divot.
I looked at epoxy and CA, but settled on Testors plastic cement or "model airplane glue" because it looked like it was best at fusing with the mini-playfield's plastic. The liquid cement had no body to it, but the gel was too thick. So I used the liquid to thin the gel into something that was somewhat self-leveling. I also used the liquid to "prime" the plastic, which seemed to offer some tooth to the gel mixture. The divot didn't need much fill, but I made two or three tiny glue applications before I was happy.
Testors liquid and gel.
Filled divot.
Next I set about removing everything from the old mini-playfield including the riveted switch brackets. Only the tip of the drill bit was need to remove rivets. I wrapped the rest of the drill with tape to protect the switch wiring.
Taped drill bit.
Extracted wire harness.
As of 2025 the red and yellow decal at the back of the mini-playfield had not been reproduced. So I needed to salvage the old one. I used up-side-down canned air and the decal popped right off. Residual adhesive was cleaned away with Goo Gone. I scanned the decal for anyone wishing to mess with it. Scan1 Scan2
Canned air.
Although I had a new main decal, I tried removing the old one. Per a suggestion I found on the Internet, I submerged the whole mini-playfield in hot water to soften the adhesive. As shown below, the white didn't survive. This was officially the point of no return.
Failed decal removal.
The flash lamp mounting standoffs were in the way of the red and yellow decal. There was no good way to maneuver the decal with exposed adhesive. I used what I call the "tab method". I applied 3M 467MP transfer tape to the decal with an extended tab of backing paper at one end. The transfer tape was trimmed to size and the adhesive was rubbed off the exposed tap. Then, without any exposed adhesive, I could carefully position the decal with painter's tape. Then I pulled the tab back on itself, exposing the adhesive while removing the painter's tape as I went.
Pulling out the backing paper from left to right.
I similarly applied the new main decal. This wasn't really a "decal", but a thicker, stiff piece of plastic with no pre-applied adhesive. Adhesive was used toward the top, but the decal is mostly held in place by the various hardware pieces. Again, I used 3M 467MP transfer tape and left a pull tab on one side.
Transfer tape applied and trimmed.
Pulling out the backing paper from left to right.
The transfer tape adhesive was not perfectly transparent, but could be much improved by carefully burnishing the decals with the back of a finger nail.
I didn't want to go back to concealing the red mini-post mounting screws. I cut a hole in the decal at each mini-post location and switched from the original flat-head screws to truss-head screws.
Truss-head versus flat-head screws.
Red mini-posts installed.
The mini-playfield had a ring on each side. But the lateral ring tension had warped the old mini-playfield. Plus the rings were clunky looking. I replaced the rings with some guardrails made from 1⁄8" polycarbonate. The rails are about 1 7⁄8" long and 3⁄8" wide with 1⁄4" holes spaced 1 1⁄2" apart. The rails simply rest on the shoulders of the metal posts and should virtually disappear after the game is fully assembled. Mini-playfield ball speeds are low and the ball would have to roll uphill to hit the rails. So I expect the rails to act as more of a safety net than something that will regularly interact with the ball. For more info on how I make plastics, see my Taxi and Millionaire repair pages.
Polycarbonate guardrails.
Clunky intended ring arrangement.
Replacement left guardrail.
Replacement right guardrail.
The flash lamp sockets and upper lamp board were attached to the mini-playfield with sheet metal screws. I didn't want to risk driving sheet metal screws into my new mini-playfield, so I switched to 6-32 machine screws and pre-tapped the mounting standoffs. For a few extra threads in the flash lamp standoffs, I followed up with a bottom tap.
Implementing the new mini-playfield was a spectacular pain in the ass. I spent weeks on this one sub-project. Much of that time was just mental problem solving and thinking through orders of operation. I wouldn't recommend replacing your existing mini-playfield unless it's completely wrecked.